hugo/tpl/os/os.go

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// Copyright 2017 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package os
import (
"errors"
"fmt"
_os "os"
"github.com/gohugoio/hugo/deps"
"github.com/spf13/afero"
"github.com/spf13/cast"
)
// New returns a new instance of the os-namespaced template functions.
func New(deps *deps.Deps) *Namespace {
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// Since Hugo 0.38 we can have multiple content dirs. This can make it hard to
// reason about where the file is placed relative to the project root.
// To make the {{ readFile .Filename }} variant just work, we create a composite
// filesystem that first checks the work dir fs and then the content fs.
var rfs afero.Fs
if deps.Fs != nil {
rfs = deps.Fs.WorkingDir
if deps.PathSpec != nil && deps.PathSpec.BaseFs != nil {
Add Hugo Piper with SCSS support and much more Before this commit, you would have to use page bundles to do image processing etc. in Hugo. This commit adds * A new `/assets` top-level project or theme dir (configurable via `assetDir`) * A new template func, `resources.Get` which can be used to "get a resource" that can be further processed. This means that you can now do this in your templates (or shortcodes): ```bash {{ $sunset := (resources.Get "images/sunset.jpg").Fill "300x200" }} ``` This also adds a new `extended` build tag that enables powerful SCSS/SASS support with source maps. To compile this from source, you will also need a C compiler installed: ``` HUGO_BUILD_TAGS=extended mage install ``` Note that you can use output of the SCSS processing later in a non-SCSSS-enabled Hugo. The `SCSS` processor is a _Resource transformation step_ and it can be chained with the many others in a pipeline: ```bash {{ $css := resources.Get "styles.scss" | resources.ToCSS | resources.PostCSS | resources.Minify | resources.Fingerprint }} <link rel="stylesheet" href="{{ $styles.RelPermalink }}" integrity="{{ $styles.Data.Digest }}" media="screen"> ``` The transformation funcs above have aliases, so it can be shortened to: ```bash {{ $css := resources.Get "styles.scss" | toCSS | postCSS | minify | fingerprint }} <link rel="stylesheet" href="{{ $styles.RelPermalink }}" integrity="{{ $styles.Data.Digest }}" media="screen"> ``` A quick tip would be to avoid the fingerprinting part, and possibly also the not-superfast `postCSS` when you're doing development, as it allows Hugo to be smarter about the rebuilding. Documentation will follow, but have a look at the demo repo in https://github.com/bep/hugo-sass-test New functions to create `Resource` objects: * `resources.Get` (see above) * `resources.FromString`: Create a Resource from a string. New `Resource` transformation funcs: * `resources.ToCSS`: Compile `SCSS` or `SASS` into `CSS`. * `resources.PostCSS`: Process your CSS with PostCSS. Config file support (project or theme or passed as an option). * `resources.Minify`: Currently supports `css`, `js`, `json`, `html`, `svg`, `xml`. * `resources.Fingerprint`: Creates a fingerprinted version of the given Resource with Subresource Integrity.. * `resources.Concat`: Concatenates a list of Resource objects. Think of this as a poor man's bundler. * `resources.ExecuteAsTemplate`: Parses and executes the given Resource and data context (e.g. .Site) as a Go template. Fixes #4381 Fixes #4903 Fixes #4858
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rfs = afero.NewReadOnlyFs(afero.NewCopyOnWriteFs(deps.PathSpec.BaseFs.Content.Fs, deps.Fs.WorkingDir))
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}
}
return &Namespace{
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readFileFs: rfs,
deps: deps,
}
}
// Namespace provides template functions for the "os" namespace.
type Namespace struct {
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readFileFs afero.Fs
deps *deps.Deps
}
// Getenv retrieves the value of the environment variable named by the key.
// It returns the value, which will be empty if the variable is not present.
func (ns *Namespace) Getenv(key interface{}) (string, error) {
skey, err := cast.ToStringE(key)
if err != nil {
return "", nil
}
return _os.Getenv(skey), nil
}
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// readFile reads the file named by filename in the given filesystem
// and returns the contents as a string.
// There is a upper size limit set at 1 megabytes.
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func readFile(fs afero.Fs, filename string) (string, error) {
if filename == "" {
return "", errors.New("readFile needs a filename")
}
if info, err := fs.Stat(filename); err == nil {
if info.Size() > 1000000 {
return "", fmt.Errorf("File %q is too big", filename)
}
} else {
return "", err
}
b, err := afero.ReadFile(fs, filename)
if err != nil {
return "", err
}
return string(b), nil
}
// ReadFile reads the file named by filename relative to the configured WorkingDir.
// It returns the contents as a string.
// There is an upper size limit set at 1 megabytes.
func (ns *Namespace) ReadFile(i interface{}) (string, error) {
s, err := cast.ToStringE(i)
if err != nil {
return "", err
}
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return readFile(ns.readFileFs, s)
}
// ReadDir lists the directory contents relative to the configured WorkingDir.
func (ns *Namespace) ReadDir(i interface{}) ([]_os.FileInfo, error) {
path, err := cast.ToStringE(i)
if err != nil {
return nil, err
}
list, err := afero.ReadDir(ns.deps.Fs.WorkingDir, path)
if err != nil {
return nil, fmt.Errorf("Failed to read Directory %s with error message %s", path, err)
}
return list, nil
}
// FileExists checks whether a file exists under the given path.
func (ns *Namespace) FileExists(i interface{}) (bool, error) {
path, err := cast.ToStringE(i)
if err != nil {
return false, err
}
if path == "" {
return false, errors.New("fileExists needs a path to a file")
}
status, err := afero.Exists(ns.readFileFs, path)
if err != nil {
return false, err
}
return status, nil
}